Observation of the fine structure for rovibronic spectral lines in visible part of emission spectra of D2D_2

For the first time in visible part of the $D_2$ emission spectrum the pseudo doublets representing partly resolved fine structure of rovibronic lines have been observed. They are characterized by splitting values about 0.2 cm$^{-1}$ and relative intensity of the doublet components close to 2.0. It is shown that they are determined by triplet splitting in lower rovibronic levels of various $^3\Lambda_g^\pm \to c^3\Pi_u^-$ electronic transitions. It is proposed to use an existence of such partly resolved fine structure patterns for identification of numerous unassigned spectral lines of the $D_2$ molecule coming from great variety of triplet "gerade" electronic states to vibro-rotational levels of the $c^3\Pi_u^-$ state.Comment: 6 pages, including 2 figures and 1 table; submitted to Phys.Rev.Let

Effective Action of Composite Fields for General Gauge Theories in BLT-Covariant Formalism

The gauge dependence of the effective action of composite fields for general gauge theories in the framework of the quantization method by Batalin, Lavrov and Tyutin is studied. The corresponding Ward identities are obtained. The variation of composite fields effective action is found in terms of new set of operators depending on composite field. The theorem of the on-shell gauge fixing independence for the effective action of composite fields in such formalism is proved. brief discussion of gravitational-vector induced interaction for Maxwell theory with composite fields is given.Comment: Typos corrected. Latex fil

Two mechanisms of pseudogap formation in Bi-2201: Evidence from the c-axis magnetoresistance

Measurements of the c-axis resistivity and magnetoresistance have been used to investigate the pseudogap (PG) behavior in Bi_{2+z}Sr_{2-x-z}La_xCuO_y (Bi-2201) crystals at various hole densities. While the PG opening temperature T* increases with decreasing hole doping, the magnetic-field sensitivity of the PG is found to have a very different trend: it appears at lower temperatures in more underdoped samples and vanishes in non-superconducting samples. These data suggest that besides the field-insensitive pseudogap emerging at T*, a distinct one is formed above T_c as a precursor to superconductivity.Comment: 7 pages, 6 figures, accepted for publication in Europhysics Letters (initially submitted to PRL on 14 June 2000